The effect of fish oil on bone resorption following pulp exposure in rats

Proresolving Mediators in Endodontics: A Systematic Review

INTRODUCTION

Proresolving lipid mediators are specialized molecules (SPMs) involved in the active resolution of the inflammatory process by regulating tissue homeostasis. The aim of this study was to investigate the scientific literature to assess the potential of SPMs as an adjunct in the treatment of endodontic infection.

METHODS

Three electronic databases (PubMed, Web of Science, and Scopus) were searched from their inception until February 2020 (PROSPERO CRD42020164743). Supplemental research was performed by screening the references of the relevant studies eligible for inclusion. A quality assessment of animal studies was performed using the Animal Research: Reporting of In Vivo Experiments guidelines, whereas the Systematic Review Centre for Laboratory animal Experimentation Risk of Bias tool was used to assess the risk of bias.

RESULTS

A total of 3295 records were screened, and 8 articles meeting the criteria were included for this qualitative review. The eligible studies showed a high to moderate overall quality and a low to moderate risk of bias. SPMs positively affected the development of pulpitis and apical periodontitis in experimental animal models. The early treatment of pulpitis with the topical application of SPMs was beneficial to control inflammation within 24 hours from contamination. In addition, SPMs delivered within the root canals after disinfection were found effective in promoting periapical healing.

CONCLUSIONS

Our findings suggest that SPMs may play a role in the inception and treatment of pulpal-periapical diseases, and they should be considered for future research for developing new therapeutics as an adjunct to endodontic treatment.

Effects of omega-3 fatty acids and aspirin on Porphyromonas gingivalis-induced periodontitis in rats

BACKGROUND

Periodontitis is a common chronic inflammatory disease caused by bacteria which can result in periodontal tissue inflammation, as well as alveolar bone resorption. The purpose of this study was to evaluate the effects of omega-3 fatty acids plus aspirin (ASA) on ligature-induced periodontitis in rats.

METHODS

Ninety-six male Sprague-Dawley (SD) rats (age 6 weeks) were randomly divided into eight groups (n = 12 each) and had ligatures placed for 7 days, followed by daily treatment with specific drug regimens for 14 days. The rats were sacrificed 20 days after drug treatment, and their maxillary were subjected to histomorphometric analysis. RAW264.7 cells were cultured with lipopolysaccharide (LPS) or receptor activator (NF)-κB ligand (RANKL), and treated with various concentrations of omega-3 and ASA. Then, cyclooxygenase (COX-2), inducible nitric oxide synthase (iNOS) protein expression and receptor activator of nuclear factor κ B (RANK), tartrate-resistant acid phosphatase (TRAP), matrix metalloproteinase-9 (MMP-9), MMP-2, and Cathepsin-K gene expression were detected.

RESULTS

The administration of omega-3 fatty acids and aspirin significantly inhibited tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in serum of rats. Histomorphometric analysis showed omega-3 fatty acids plus aspirin promoted alveolar bone increase. Omega-3 fatty acids only, aspirin only, or omega-3 fatty acids plus aspirin also inhibited the protein expressions of COX-2 and iNOS in LPS-stimulated RAW264.7 cells. In addition, omega-3 combined with ASA also inhibited the RANKL-induced gene expressions of MMPs in dose-dependent manners.

CONCLUSION

These results demonstrate that omega-3 fatty acids plus aspirin could decrease alveolar bone loss, while simultaneously increasing the protection against periodontal inflammation.

Omega 3 Fatty Acids Reduce Bone Resorption While Promoting Bone Generation in Rat Apical Periodontitis

INTRODUCTION

This study evaluated the effects of the dietary supplement omega 3 polyunsaturated fatty acids (ω-3 PUFAs) on pulp exposure-induced apical periodontitis (AP) in rats.

METHODS

Twenty-eight male rats were divided into groups: control untreated rats (C), control rats treated with ω-3 PUFAs alone (C-O), rats with pulp exposure-induced AP, and rats with pulp exposure-induced AP treated with ω-3 PUFAs (AP-O). The ω-3 PUFAs were administered orally, once a day, for 15 days before pulp exposure and, subsequently, 30 days after pulp exposure. Rats were killed 30 days after pulp exposure, and jaws were subjected to histologic and immunohistochemical analyses. Immunohistochemical analyses were performed to detect tartrate-resistant acid phosphatase-positive osteoclasts and osteocalcin-positive osteoblasts on the bone surface of periapical area. Results were statistically evaluated by using analysis of variance and Tukey honestly significant difference, and P < .05 was considered statistically significant.

RESULTS

The bone resorption lesion was significantly larger in the AP group compared with AP-O, C, and C-O groups (P < .05). The level of inflammatory cell infiltration was significantly elevated, and the number of tartrate-resistant acid phosphatase-positive osteoclasts was significantly higher in the periapical lesions of the AP group compared with AP-O, C, and C-O groups (P < .05). The number of osteocalcin-positive osteoblasts was significantly increased in the AP-O group compared with the AP group (P > .05).

CONCLUSIONS

Supplementation with ω-3 PUFAs not only suppresses bone resorption but also promotes new bone formation in the periapical area of rats with AP in conjunction with downregulation of inflammatory cell infiltration into the lesion.

N-3 polyunsaturated fatty acid effect in periodontal disease: state of art and possible mechanisms involved

Anti-inflammatory properties have been widely reported for n-3 polyunsaturated fatty acids (PUFAs) and some studies have been focalized on their possible role in the modulation of gingivitis and alveolar bone resorption in periodontal disease (PD). Increased formation of arachidonic acid-derived inflammatory eicosanoids and augmented oxidative stress are two molecular mechanisms pathogenetically involved in the progression of PD and known to be inhibited by n-3 PUFAs in PD setting. The present review will focus also on other molecular pathways and factors known to be altered in the development of PD and known to be subject to n-3 PUFA modulation in other pathological settings different from PD. Overall, the available findings strongly encourage further experimental studies on animals subject to experimental PD and treated with n-3 PUFAs, long term n-3 PUFA intervention studies on PD patients and molecular studies to identify additional potential molecular routes of n-3 PUFA action in PD.

Omega-3 fatty acid regulates inflammatory cytokine/mediator messenger RNA expression in Porphyromonas gingivalis-induced experimental periodontal disease

INTRODUCTION

Porphyromonas gingivalis is strongly implicated in the etiology of adult periodontitis by inducing inflammatory cytokines, resulting in gingival and periodontal tissue inflammation and alveolar bone resorption. This study tested the hypothesis that supplementing the diet with omega-3 fatty acid (omega-3 FA; i.e. fish oil) would exert anti-inflammatory effects in the gingival tissues of P. gingivalis-infected rats.

METHODS

Rats were fed either fish oil or corn oil diets ad libitum for 22 weeks and infected with P. gingivalis strain 381 or strain A7A1-28. After sacrifice, rat gingival tissues were excised and the RNA was isolated and analyzed for proinflammatory mediators [interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), IL-6], T helper type 1 and type 2 cytokines [interferon-gamma (IFN-gamma), IL-4, IL-10), antioxidant enzymes [catalase (CAT), superoxide dismutase (SOD)], and genes critical for eicosanoid mediator production [cyclo-oxygenase-2 (COX-2), 5-lipoxygenase (5-LO)] by reverse transcription-polymerase chain reaction using rat-specific primers.

RESULTS

Rats on the omega-3 FA diet exhibited decreased proinflammatory cytokine gene expression (IL-1beta, TNF-alpha) and enhanced IFN-gamma, CAT and SOD messenger RNA expression compared to rats fed a corn oil diet, supporting a diet-induced modulation of host inflammatory reactions. Analyses of alveolar bone resorption in the rats related to gene expression profiles demonstrated significant positive correlations with IL-1beta, IL-6 and COX-2 and negative correlations with CAT and SOD.

CONCLUSION

These findings suggest that diets enriched for omega-3 FA modulate the local gingival inflammatory milieu of the host following oral P. gingivalis infection, which impacts on alveolar bone resorption in rats.

Omega-3 fatty acid effect on alveolar bone loss in rats

Gingival inflammation and alveolar bone resorption are hallmarks of adult periodontitis, elicited in response to oral micro-organisms such as Porphyromonas gingivalis. We hypothesized that omega (omega)-3 fatty acids (FA) dietary supplementation would modulate inflammatory reactions leading to periodontal disease in infected rats. Rats were fed fish oil (omega-3 FA) or corn oil (n-6 FA) diets for 22 weeks and were infected with P. gingivalis. Rats on the omega-3 FA diet exhibited elevated serum levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), documenting diet-induced changes. PCR analyses demonstrated that rats were orally colonized by P. gingivalis; increased IgG antibody levels substantiated this infection. P. gingivalis-infected rats treated with omega-3 FA had significantly less alveolar bone resorption. These results demonstrated the effectiveness of an omega-3 FA-supplemented diet in modulating alveolar bone resorption following P. gingivalis infection, and supported that omega-3 FA may be a useful adjunct in the treatment of periodontal disease.